Pancreatitis

Pancreatitis is inflammation of the pancreas. It is usually divided into two categories, acute pancreatitis and chronic pancreatitis.

It is said that pancreatitis (acute and chronic) accounts for 3% of all cases of abdominal pain in the U.K. It can be a serious condition, with very significant mortality figures if it is severe.

Acute pancreatitis

Features

Severe abdominal pain often radiating through to the back.
Nausea, vomiting and loss of appetite.
Severe illness, sometimes requiring admission to intensive care and sometimes fatal.
Recovery may be followed by development of pancreatic pseudocyst, pancreatic dysfunction (malabsorption) or diabetes.

Causes

The most common causes of pancreatitis, accounting for more than 85% of all cases of pancreatitis in Western countries are chronic alcoholism and gallstones. Other causes include trauma (as from a steering wheel in an automobile accident), infection (the mumps virus being the most common), drugs (the diuretics furosemide and thiazides, and some antiretrovirals are common causes, as well as azathioprine and morphine), and cancer.

Gallstones that travel down the common bile duct and which subsequently get stuck in the Ampulla of Vater can cause obstruction in the outflow of pancreatic juices from the pancreas into the duodenum. The backflow of these digestive juices causes lysis (dissolving) of pancreatic cells and subsequent pancreatitis.

A common mnemonic for the causes of pancreatitis is: "GET SMASHED", an acronym for Gallstones, Ethanol (alcohol), Trauma, Steroids, Mumps, Autoimmune, Scorpion venom, Hyper- (calcemia and triglyceridemia), ERCP and Drugs.

Pathogenesis

The exocrine pancreas produces a variety of enzymes, such as proteases, lipases and saccharidases. These enzymes conntribute to food digestion by breaking down food tissues. In acute pancreatitis, the worst offender among these enzymes may well be the protease trypsinogen which converts to the active trypsin which is most responsible for auto-digestion of the pancreas which causes the pain and complications of pancreatitis.

Diagnosis

Important biochemical markers for pancreatitis are serum amylase and lipase levels. Amylase and lipase levels can rise to more than a hundred times normal levels in cases of acute pancreatitis.

In addition, in predicting the prognosis, there are several factors that are known to impact negatively on survival: the more of these that are present, the graver the patient's condition is (these are known as the Ranson or Imrie criteria):

age greater than 55 years at admission or diagnosis
a white blood cell count of > 16,000/µl at admission or diagnosis
blood glucose > 11 mmol/L (>200 mg/dL) at admission or diagnosis
serum LDH > 400 IU/L at admission or diagnosis
serum AST >256 IU/L at admission or diagnosis
fall in hematocrit by more than 10 percent in the first 48 hours of admission
fluid deficit of > 4 L in the first 48 hours of admission
hypocalcemia (serum calcium < 1.0 mmol/L (<8.0 mg/dL) in the first 48 hours of admission
hypoxemia (P_O₂ < 60 mmHg in the first 48 hours of admission
increase in BUN to >1.98 mmol/L (>5 mg/dL) after IV fluid hydration in the first 48 hours of admission
hypoalbuminemia (albuminm <32 g/L (<3.2 g/dL) in the first 48 hours of admission
Acute physiology and chronic health evaluation (APACHE II) score > 12 points
hemorrhagic peritoneal fluid
obesity
indicators of organ failure
hypotension (SBP <90 mmHG) or tachycardia > 130 bpm
P_O₂ <60 mmHg
Oliguria (<50 mL?h) or increasing BUN and creatinine
serum calcium < 1.90 mmol/L (<8.0 mg/dL) or serum albumin <33 g/L (<3.2.g/dL)>

Classification by severity

Acute pancreatitis can be further divided in mild and severe pancreatitis. Mostly the Atlanta classification (1992) is used. In severe pancreatitis serious amount of necrosis determine the further clinical outcome. About 20% of the acute pancreatitis are severe with a mortality of about 20%. This is an important classification as severe pancreatits will need intensive care therapy whereas mild pancreatits can be treated on the common ward.

Necrosis will be followed by an systemic inflammation response syndrom (SIRS) and will determin the immediate clinical course. The further clinical course is then determined by bacterial infection. SIRS is the cause bacterial translocation from the patients colon.

There are several ways to help distinguishe between these two forms. One is the above mentioned Ranson Score.

Treatment

Supportive for shock.
Pain relief
Enzyme inhibitors are not proven to work.
While often severe, the disease is essentially self limiting.

In the management of acute pancreatitis, the treatment is to stop feeding the patient, giving him nothing by mouth, giving intravenous fluids to prevent dehydration. As the pancreas is stimulated to secrete enzymes by the presence of food in the stomach, having no food pass through the system allows the pancreas to rest.

Chronic pancreatitis

Chronic pancreatitis can present as episodes of acute inflammation in a previously injured pancreas, or as chronic damage with persistent pain or malabsorption. The causes of relapsing chronic pancreatitis asre similar to those of acute pancreatits, though gallstone-associated pancreatitis is predominantly acute or relapsing-acute in nature, and more cases of chronic pancreatitis are of undetermined or idiopathic origin.

Patients with chronic pancreatitis can present with persistent abdominal pain or steatorrhea.

Among American adults, chronic pancreatitis most often occurs from the cumulative pancreatic destruction caused by repeated alcohol-induced episodes of acute pancreatitis. Cystic fibrosis is the most common cause of chronic pancreatitis in children. In up to one quarter of cases, no cause can be found. In other parts of the world, severe protein-calorie malnutrition is a common cause.

Serum amylase and lipase may well not be elevated in chronic pancreatitis. Pancreatic calcification can often be seen on x-ray.

Treatment is directed, when possible, to the underlying cause, and to relief of the pain and malabsorption. Replacement pancreatic enzymes have proven effective in treating the malabsorption and steatorrhea.